RESULTADOS Y DISCUSIÓN 4.1 De la concentración de antocianinas de Mashua
4.4 Validar el µPADma como multi sensor de pH ecológico en diferentes productos alimenticios
NdrYAG laser treatment was performed using a high power non-contact technique as described in Chapter 5, 5.2.3. Nodules of exophytic tumour causing prosthesis obstruction were vaporised and gradually shaved back to within 2-3mm of the oesophageal wall; flat parts of the tumour were
coagulated and allowed to slough. Tumour overgrowing and obstructing the proximal end of a prosthesis almost invariably could not be negotiated with the endoscope and was recanalised in a prograde fashion. As the obstructing tumour was short in most cases, complete recanalisation was usually possible in one session. For prostheses obstructed by tumour at their distal end, an endoscope slim enough to pass through an Atkinson or Celestin tube was used instead of a large calibre therapeutic endoscope. Treatment of tumour undergrowth is technically more difficult than that of overgrowth because of orientation and laser targeting problems while the endoscope is confined within the prosthesis. In order to secure a good lumen, tube manipulation was considered necessary in some patients after laser recanalisation; in one patient a second prosthesis was inserted and impacted into the first from above. Manipulation of tube position was performed with an Atkinson introducer. In some cases, particularly if the tumour was very hard and the prosthesis had been in situ for several months, this could not be achieved as
it proved impossible to obtain a strong enough grip (especially with Celestin tubes). Three examples of prosthesis tumour overgrowth are shown in Figures 7.1 to 7.3.
Dysphagia was graded on a five point scale as described in Chapter 5, 5.2.4. All patients were assessed prior to and following treatment while still in hospital and subsequently by telephone by an experienced research nurse (D. Grigg- Rampton, M. Tulloch, S. Thorpe).
7.6.3 Statistics
Dysphagia scores before and after treatment were compared using the Wilcoxon signed rank test. Significance was set at the 5% level (p<0.05).
7.7 Results
In all eleven patients with overgrowth, the obstructing tumour was
successfully recanalised with the laser. In three patients, the prostheses were shifted up using the Nottingham introducer to cover the area of overgrowing tumour after laser therapy; additional laser treatment was only required in one patient. Treatment enabled all eleven patients to sw allow a semi-solid for most of their survival.
One of the two patients with tumour obstruction of the distal end of the prosthesis underwent laser therapy using an Olympus XQ 20 endoscope passed through the tube. In the other, the prosthesis was shifted downwards with the Nottingham introducer to cover the obstructing tumour; this uncovered tumour above the upper end of the prosthesis which was subsequently successfully treated with the laser.
One of the patients presented with worsening dysphagia due to tumour obstruction of both the upper and lower ends of an Atkinson tube which had been inserted 17 weeks previously and had allowed her to eat a semi-solid diet. The dominant obstruction was at the upper end of the tube and this was successfully treated by laser therapy on four occasions over a period of 17 weeks enabling her to eat a semi-solid diet once again. She subsequently developed an extrinsic stricture proximal to the prosthesis which was not amenable to laser therapy. This was dilated and a short (9 cm) Celestin tube
Figure 7.1: A, A typical prosthesis tum our overgrowth. Polypoid tum our is seen to overgrow a Celestin prosthesis in a patient with adenocarcinoma of the cardia intubated 14 months previously. B, Appearance following laser treatment; the prosthesis was subsequently shifted upw ards by 5cm to cover the area of overgrowing tumour.
Figure 7.2: A less typical example of prosthesis tum our overgrowth. The obstructing tum our in this patient w ith adenocarcinoma of the cardia intubated 7 m onths previously, may have been m isdiagnosed as an odem atous mucosal fold resulting from pressure of the prosthesis on the oesophageal wall. Initial superficial treatm ent w ith the laser revealed obviously neoplastic tissue which was subsequently vaporised.
Figure 7.3: A, A further example of tum our overgrowting and obstructing an Atkinson prosthesis which had functioned well for 9 m onths in a patient with adenocarcinoma of the cardia. The mucosa is diffusely abnormal and there is only a pinpoint lumen. B, Barium swallow study shows a tight irregular stricture and only a trickle of contrast passing through into the prosthesis; the proximal oesophagus is dilated and contains food residue. C, Appearance following laser treatment. Treatment proceeded centrifugally starting at the luminal tum our surface, until the buried prosthesis was revealed.
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placed through the stricture with its distal end impacted into the funnel of the Atkinson tube below. This enabled the patient to swallow semi-solids until her death 6 weeks later.
The median pre-treatment dysphagia grade was 4; 10 of the 14 patients had complete dysphagia at presentation. All patients except one derived an
improvement in swallowing of at least one grade on the dysphagia scale after treatment and ten patients improved by two grades. After treatment, the median dysphagia grade during the patients' remaining survival was 2, an improvement which was significant at the 1% level on statistical analysis. Eight patients required only one or two endoscopic treatments and the others up to five. Median survival was 9 weeks (range 3-36 weeks). Eleven patients died of relentless progression of their malignancy; two suffered recurrent pulmonary aspiration which contributed at least partly to their death. One patient died of a myocardial infarction. Median lifetime hospital stay for endoscopic therapy was 5 days (range 3-17 days). No serious procedure related complications occurred.
7.8 Discussion
A potential danger of recanalising an oesophageal tube obstructed by tumour with the Nd:YAG laser is ignition of the prosthesis. Mousseau-Barbin tubes have been reported to ignite (Carter and Smith 1988) and if laser treatment is to be attempted in patients with such tubes in situ, carbon dioxide rather than air should be used for cooling the fibre. Several patients with this type of prosthesis have undergone laser treatment in our unit after distal
displacement without any accidents. Atkinson and Celestin tubes do not ignite (but the burning rubber smells foul), so it is safe to use air for cooling the laser fibre when treating patients with such prostheses in situ.
Ethanol injection treatment and to a lesser extent BICAP therapy which have been discussed in Chapter 2, 2.4 may also prove useful for managing
prosthesis tumour obstruction. The main advantage of laser therapy in this context, is the ability to vaporise tissue and immediately establish an adequate lumen through the obstructing tumour. With the other techniques
mentioned above, establishment of an adequate lumen and improvement in swallowing is usually delayed for few days until necrosed tumour sloughs off; in addition, more treatment sessions may be required than with laser therapy.
Tube manipulation after laser therapy should be attempted with great caution if deemed necessary. Shifting prostheses which have been in situ for several months carries a definite risk of perforation. In addition as it is not possible to estimate the axial extent of the tumour, upward displacement of a prosthesis may expose tumour below its distal end which may prove more difficult to treat with the laser than proximal overgrowth. Although shifting of a prosthesis to cover short obstructing tumours after laser therapy was
performed without complications in four patients in the present study, it is inappropriate for most cases. Given the very limited patient survival, good long-term palliation can be achieved with only a few laser procedures and the potential risks of tube manipulation avoided. It should be noted that tube manipulation without prior laser treatment may not be technically possible (because overgrowing tumours usually cause tight stenoses preventing insertion of the Nottingham introducer) and carries a greater risk of perforation as excess force is often required to shift the prosthesis.
Two patients in the series had undergone intubation at the time of
laparotomy. Surgically implanted prostheses are sutured to the gastric wall in order to prevent proximal displacement. It is important that the therapeutic endoscopist is cognizant of this information as attempts to shift the prosthesis proximally can result in tearing of the gastric wall with disastrous
consequences. With current endoscopic techniques and equipment it is rarely necessary to resort to surgical intubation.
In conclusion, the results of the present study demonstrate that laser treatment for prosthesis tumour obstruction is both feasible and safe and validate an active management approach for most of these patients.
Treatment enables patients to resume the consumption of a "tube diet" and as the obstructing tumour is usually short, long-term palliation can be achieved with only one or two procedures during a patient's lifetime.